Conventional retroreflective fibers, threads, yarns, and the like that are used in fabrics are generally formed using a binder to attach glass bead retroreflectors to the surface of natural or synthetic fibers from which the threads, yams, and the like are formed. However, since a fiber, thread, yarn, and the like has glass bead retroreflectors exposed on its surface, this configuration offers little protection against abrasion and degradation of the retroreflectors. Further, the fabrics and materials to which the retroreflectors are attached tend to have low levels of retroreflectivity, and the retroreflectors themselves have limited life expectancies with regard to effectiveness. Also, exposed glass bead retroreflectors can also abrade textile manufacturing equipment, and can also degrade the fabric material to which the retroreflectors are attached. In addition, exposed glass bead retroreflectors can lose their retroreflective properties when wet. In addition, conventional glass retroreflectors or lenses are randomly attached to the fabrics and materials, and are of different and random shapes and sizes, further reducing the effectiveness of the retroreflectors.
Another conventional approach includes forming retroreflective threads or yarns by attaching glass beads, which are optionally metalized with a reflective coating, to a sheet of material, and then slitting, dicing, or cutting the sheet of material into narrow strips of material.
In some applications, two sheets of material are attached to each other, wherein each sheet has a first surface that includes attached glass bead retroreflectors, and a second surface that is free of glass bead retroreflectors, wherein the second surfaces of the two sheets of material are attached to each other, for example, by being laminated back-to-back. In this manner, glass bead retroreflectors are exposed on both sides of the combined sheets of material. The combined sheets are then slit, diced, or cut into narrow strips of material. In another approach, glass bead retroreflectors are adhered with a binder to both sides of the same sheet of material, and the sheet is slit, diced, or cut into narrow strips of material.
Another conventional approach is to form corner cube retroreflectors on a sheet of material, metalize the corner cube retroreflectors, and then slit the sheet of material to form strips of single-sided corner cube films. Often, two strips of the metalized corner cube films are attached to each other, back-to-back, followed by slitting the combined strips of corner cube films into narrow widths to form a two-sided retroreflective fiber.
Such conventional methods of forming retroreflective fibers are described, for example, in U.S. Pat. No. 4,576,850, issued Mar. 18, 1986, entitled “Shaped Plastic Articles Having Replicated Microstructure Surfaces,” and as described in U.S. Pat. No. 3,689,346, issued Sep. 5, 1972, entitled “Method for Producing Retroreflective Material,” the content of each being incorporated herein by reference in its entirety.
However, conventional retroreflective fibers include non-retroreflecting edges, which can change the appearance of the fiber. In addition, such conventional retroreflective fibers do not include a reinforcing inner layer, causing the fibers to be insufficiently fragile. As such, it is undesirable to use conventional retroreflective fibers to form fabrics by sewing, knitting, embroidering, and the like.